Dell has announced refreshes to its XPS line of Ultrabooks, with the XPS 15 is getting a 3600 x 1800 resolution display, hardware updates for the XPS 13 and formal announcement of the XPS 11. 

Starting at the top, the Dell XPS 15 is a powerhouse, with a 3200 x 1800 pixel resolution UltraSharp display. That equates to 235ppi, meaning that Apple's "world's highest resolution notebook" tag on the MacBook Pro with Retina display no longer stands and challenging the Chromebook Pixel's sharpness. 

This powerhouse notebook gets options for fourth-gen Intel Core processors, up to Core i7, with the option of discrete Nvidia graphics for those who really need to push the pixels.

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You'll be able to get up to 1TB of storage in the XPS 15, along with the 32GB SSD, in it's slim body, with a great carbonfibre base. We've had the chance for a quick play with a pre-production sample, so be sure to read our first impressions.

READ: Dell XPS 15 pictures and hands-on

Moving down a size, the XPS 13 has been updated too, now offering fourth-gen Intel Core processors up to i7.

The XPS 13 doesn't get a bump in resolution, but the 13.3-inch 1920 x 1080 pixel display is now touch enabled, as well as being topped by Corning Gorilla Glass for protection. We really liked the previous XPS 13, with its great design and how well it packs the display into a compact frame.

READ: Dell XPS 13 review

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Finally the Dell XPS 11 is pitched as a two-in-one, offering a keyboard that will rotate around to the back of the display so it can be used as a tablet. The XPS 11 was announced in June 2013 as a prototype, but is now official. 

The XPS 11, like the XPS 15, offers and UltraSharp display, this time with 2560 x 1440 pixels (253ppi) on the 11.6-inch display.

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Constructed from machined aluminium, carbonfibre and Gorilla Glass, one of the clever unique features of the XPS 11 is the finish of the keyboard. It's flattened, designed so that those keys won't be knocked off if they're flat on a desk, but still providing travel when typing. 

We don't have the final pricing or availability for the new XPS models, but we will update as soon as we do.

Dell also today announced new Venue Pro Windows 8.1 tablets: the Venue 8 Pro and the Venue 11 Pro.